In response to PA-06-329, Epidemiology of Drug Abuse, this exploratory project proposes to use an existing nationally representative dataset to assess the relationships among sexual orientation, perceived discrimination, substance abuse, mental health, and treatment utilization in the United States. Past research has generally found lesbian, gay and bisexual (LGB) individuals are at heightened risk for substance use and mental health disorders but these studies have been plagued by methodological limitations, including small, non-representative samples and lack of heterosexual comparison groups. To date, no large-scale nationally representative studies have examined the epidemiology of substance use and mental health disorders among self-identified LGB individuals and almost no data on treatment utilization among sexual minorities exists. Thus, we propose to conduct a secondary analysis of the 2004-2005 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), a nationally representative sample of 34,653 U.S. adults 18 years and older in the United States. The specific aims are to: (1) assess the prevalence and co-occurrence of substance use behaviors, DSM-IV substance use, mood and anxiety disorders based on sexual orientation; (2) estimate substance abuse and mental health treatment utilization based on sexual orientation among respondents with and without DSM-IV diagnoses; and (3) examine the association between perceived discrimination and substance use and mental health outcomes among sexual minorities. The proposed project will take advantage of the unique opportunities afforded by the 2004-2005 NESARC: the availability of an ample and ethnically diverse sample with large numbers of sexual minority women and men; the inclusion of multiple measures of sexual orientation; and the wealth of data on DSM-IV substance use, mood and anxiety disorders, and treatment utilization. Findings from this project will enhance understanding of the epidemiology of substance use and mental health disorders among both heterosexuals and sexual minorities in the United States, and will provide information to improve the assessment, prevention and treatment of these disorders. 7. PROJECT NARRATIVE Understanding patterns and distributions of substance abuse and mental health disorders across sub-groups based on dimensions of sexual orientation is critical for designing effective public health prevention, intervention and treatment programs. This project will examine several unexplored research questions related to the epidemiology of substance use and mental health disorders across dimensions of sexual orientation, treatment utilization among those groups and the impact of perceived discrimination on the substance use behaviors and mental health of sexual minority groups. [unreadable] [unreadable] [unreadable] [unreadable]